I want the men who've been in favour of asking for a discount to think of how they would feel if tomorrow their work place called them and said the following:
We'd like you to come into work tomorrow, give the same amount of effort you always do, dress exactly as you always do, get to work the same way as you always do, etc. but we are going to give you 50-75% of your wages. Don't worry! We still value the work you do, the effort you put in, and the fact that you are even inclined to show up.
This doesn't even relate to the question at hand.
For most of the rest of us work for somebody else. Your situation is that of somebody who works for herself, and who is freely able to set her own prices along a variable market.
To look at it as you just did makes more sense against somebody trying to justify not tipping a waitress... who usually works for somebody else, but whose actual income is derived mostly from those gratuities.
In the same way that Johns, presumably, can find a working girl (somewhere) to fit just about every price (with increased risks involved as the price goes down)... a working girl, with functioning anatomy, should have a sliding range of options based on how much financial need she has at any given moment, no matter whether one particular girl wants to partake in those options at any given time.
Truthfully, most of us do not care at what level any individual sets her prices, as we are free to avoid her or leap up to see her at our whim. It is when you look over at the neighbor's pricing trends and pass judgment on her that you are out of bounds for so doing.
Invariably, the woman stating "non-negotiable" @ $300 per hour in July... will be the one wishing for more business in early February. If you're too dense to flow with the market then that's fine... but when you sit here trying to decide whether somebody else should have that option, then you're foolish.